Duncan's 1960 Magnavox

[Alex KL-1]

Originally Posted by Mr.Duncan

Will do! - I'll check these tonight.

I'm always open to me making a mistake, perhaps I just haven't seen it yet. I did replace capacitors one at a time, while using tape to mark the wire connections (as to not lose track of the positions when replacing)

C2 did blow up - which is the reason why I replaced ALL capacitors at the same time, I probably should have replaced JUST C2 first and done testing.

I assume when I touch pins 3-through-6 of V10 it will cause the output plate of V10 to cause vertical deflection?

Why does the schematic say "DO NOT MEASURE" the plate output / Pin# 9 of V10? - The voltage doesn't seem THAT high?

The DC voltage yes, will not that high. But, with deflection working, the retrace pulse/period produces a high amplitude spike in the primary, sometimes near 1.6kV. This for every frame, aka. 60 times per second of these pulses (for vertical stage; 50 times for a lot of another countries).

[Mr.Duncan]

Okay I think I found it. I did make a wiring mistake!

C35 was connected to the wrong pin of V9 / 6BF6.

I must have been distracted, but its clearly on the wrong terminal.

Check the before/after photos below.

C35 was replaced with a MICA cap. .0051 uF @ 500v

I will remove the capacitor, check it, and reinstall (if okay) on the correct pin.

I wonder if this could have caused any harm?


Untitled by Thomas Duncan, on Flickr

tube by Thomas Duncan, on Flickr

[Alex KL-1]

Perhaps not, is worth to testing the TV now.